


A Matter of Principle

by cuckleberrywish



Series: This Much I Know [3]
Category: Doctor Who, Doctor Who (2005)
Genre: F/M, Humor, Shameless Smut
Language: English
Status: Completed
Published: 2015-09-10
Updated: 2015-09-10
Packaged: 2018-04-20 04:01:12
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,168
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4772738
Author URL: https://archiveofourown.org/users/cuckleberrywish/pseuds/cuckleberrywish
Summary: <blockquote class="userstuff">
              <p>They're just mates. That's all. Really. Any evidence to the contrary is purely circumstantial and thus should be subject to extreme scrutiny.</p>
            </blockquote>





	A Matter of Principle

**Author's Note:**

> A continuation of part 10 of This Much I Know that sprouted legs and became this abomination so I decided to post it separately. Nonetheless, it's probably not necessary to read part 10 to get the gist of what's going on here.

After their evening together (and morning, and much of the next day, if he’s honest) things change, and they don’t.

They still bicker endlessly and frequently in front of important political figures and she smacks his hands away when he eats her favourite blueberry jam with his fingers. He still tries to retreat inside himself when something goes wrong and like always, she sees the gentle melancholia in his eyes and draws it out of him. They still laugh and hold hands and object loudly and vocally when someone assumes they’re married.

Except now he knows just how soft the skin of her inner thigh is, he knows how she likes her ears nibbled, her neck kissed. He knows the divine slope of her hips, the elegant arch of her spine. He knows the galaxy of freckles across her collarbones so well he can picture them in his mind’s eye.

She still snorts and smacks him away when he tries to pay her a compliment and nearly laughs herself sick when, in a fit of gallantry, he brings her flowers that turn out to be slightly sentient and more than slightly carnivorous.

After he’s flung the flowers into the vortex and she’s finished laughing, she cups his cheek and smiles and murmurs, “Don’t bring me flowers, Spaceman.” He opens his mouth to protest and she shakes her head, withdraws her hand only to punch him gently on the arm and says, “Best mates, yeah? That’s all. No flowers. None of that rubbish.”

And then she promptly ruins the effect by kissing him enthusiastically.

It’s a perfect arrangement.

“We need rules,” she pants one day after they end up on the jump seat, the adrenaline and giddiness of a brush with death conspiring against them. Her blouse is undone and her jeans are carelessly discarded and his tie is askew, trousers yanked down. “So this doesn’t, y’know,” she gestures vaguely between them, her chest still heaving. “Mess with our friendship.”

“What sort of rules?” he asks, hurriedly replacing his clothing. He feels thoroughly undignified having a conversation with his trousers round his ankles.

“ _I don’t know!_ ” she crows, looking exasperated. “Rules!”

“Don’t your lot do this sort of thing all the time? Friends with benefits or whatever, right?” he asks, half distracted by the bounce of her breasts as she shimmies back into her jeans.

“My lot?!” Donna growls threateningly.

“Humans!” the Doctor exclaims, startled out of his pleasant daze. Donna, thankfully, deflates.

“We don’t tell our friends,” she says after some thought, sitting back on the jump seat next to him with everything (disappointingly, the Doctor thinks privately) buttoned, zipped and properly hidden. He opens his mouth to protest and she forestalls him, saying, “People won’t understand, y’know? They won’t understand that we’re just mates, they’ll make all sorts of weird insinuations and assumptions and it’ll just get uncomfortable.”

He secretly thinks they’re a great deal more than _just mates_ but wisely keeps the thought to himself. “We don’t tell anyone. Sure,” he agrees.

“Nothing and I mean _nothing_ –” she jabs a finger so close to his face he goes cross-eyed, “–dodgy around my mum and Gramps. Not so much as a breath of any of this.”

He nods fervently, still focused on the finger now pressed into his sternum.

“And we still sleep in our own beds.”

“What?!” he exclaims. He thinks this measure is a little extreme given the fact that they’d slept together (but not like that) quite a bit even before they’d… well… _slept together_. Plus, he likes a cuddle. Who doesn’t?

“You snore,” she says loftily, flicking her hair behind shoulder with a haughty flourish. And then she ducks her head so he can’t see her laughing. He sighs.

“Fine. No sleeping together,” he grumbles. “Except in extenuating circumstances.”

She quirks an eyebrow.

“Y’know, existential angst, grief from the loss of my people, horrifying and fundamentally disturbing villains, nightmares, boredom et cetera, et cetera,” he reels off nonchalantly and she snorts.

“We do have to keep _some_ boundaries, y’know.”

“I know,” he intones, his voice coming out a sight whinier than he’d planned.

“Nothing changes,” she says resolutely and he’s not sure if she’s talking to herself or to him.

Naturally, the third rule is the first to be broken.

He maintains it’s Donna’s fault for exhausting him so thoroughly that he _absolutely could not even fathom_ the idea of slouching three doors down to his own bedroom. He collapses next to her and his eyes flicker closed and he pretends not to notice her poking at his ribs persistently.

“Oi,” Donna murmurs, her lids also half-closed. “Get out of my bed you great martian lump.”

“Kicking me out straight afterward? A girl could start to feel a bit used,” the Doctor mutters in mock offense, his voice muffled by her chest– her lovely, pillowy chest that he has no desire to leave, not now and not ever.

She jabs at him again, more than half-heartedly. “But the rules.”

“It’s a dumb rule,” says the Doctor sleepily.

“A dumb rule,” she repeats and then she’s asleep.

He’s sure to skulk away before she wakes up but even so it’s the best sleep he’s ever had. He suspects she feels the same because she never kicks him out again.

The first rule is the second to be broken, though in hindsight, he thinks broken is too kind of a word to describe what’s happened.

The Doctor’s never been great at weddings but Donna drags him along to Martha’s anyways, with a very characteristic combination of threats and bribes. In the end, he figures he owes Martha this small favor after getting her family imprisoned and tortured, forcing her to roam a decimated earth for a year, and generally ruining her life. At the very least _that_ deserves showing up at her wedding.

He grins from ear to ear and sheds a secret tear or two when he sees Martha at the altar, so happy and brilliant and beautiful. He must be getting old. He never used to cry at weddings.

The Doctor glances to his right and Donna is clutching a handkerchief, her eyes teary and bright. She looks particularly lovely today, in a fluttery ice-blue dress that skims her knees, her hair down and curly around her shoulders. He puts an arm around her and she gives him a watery smile.

“She’s so beautiful,” Donna murmurs, dropping her head on his shoulder.

“Yeah,” the Doctor breaths, momentarily transfixed by the light bouncing off the crown of Donna's hair. “Lovely.”

When the Doctor gives Martha a huge hug in the receiving line, she holds him at arm’s length studying him shrewdly and says, “There’s something different about you, Doctor.”

He shrugs. “Been sleeping well.”

At the reception he watches Donna dance with Martha, guarding her drink (something fruity in a frightening shade of vivid pink) and nursing his own pint. Donna throws back her head and laughs and somewhere in the middle meets his gaze fondly. She bids Martha farewell and makes her slightly wobbly way back to him.

“Steady on,” he says grabbing her arm as she collapses into a chair next to him. Her eyes are glassy and bright and he can tell she’s had a bit too much to drink.

“It’s all just so lovely, isn’t it?” she sighs, smiling blissfully at him. “I love weddings.”

He can't help but grin at her, at how easily the facade of her cynical world view is shattered. He knows she's secretly a romantic. She's just learned to hide it.  

He's startled from his thoughts because a moment later she’s out of her chair again, tugging him up by the neck tie. He splutters for a moment and then gingerly extracts himself from her grip, grasping her hand instead.

“Where are we going?”

She just gives him a mischievous little smirk and tugs him along.

They don’t make it very far before Donna pulls him into an unused room– which he realizes belatedly is full of cleaning supplies and unused chairs– off the main corridor, kicks the door shut and springs for him, her fingers tangling in his hair. He kisses her back, slightly confused, but happy to comply, letting his hands rest on her round hips, loving the way he can feel the warmth of her skin through the thin silk of her dress. He’d felt bereft of her touch without even realizing it during the ceremony and reception. He’s a little shocked at how quickly he’s got used to feeling her close to him.

The Doctor’s brought sharply back to the present when she presses the length of her lovely body against his and nips at his earlobe, her hot hands skimming down over his stomach so that suddenly she’s fumbling with his trousers. He grasps her fingers and she looks up at him.

“Not here, surely,” the Doctor says, quirking an eyebrow at her.

“Why not? It’s a wedding. We’re practically expected to,” she drawls, and he can’t help the way his hearts quicken when she strokes him teasingly through his trousers. “Everyone’s at the party. No one will notice we’re gone, and we’ll nip back in just before the speeches.”

“But this must be violating at least fifty of those rules of yours,” he points out, his resolve quickly slipping. He can’t help it. He loves her like this, all wanton and undone.

“Those rules of _ours_ ,” she corrects primly. “And no, there’s no rule about this, as such.”

“Shagging in public places? Don’t you think there ought to be?” he squeaks.

Donna’s hands fall to her sides and she huffs out a frustrated sigh. “Look. D’you want to fuck me or not?”

The answer to that is of course, an emphatic yes, and he shows her, knotting one hand in her hair, the other deftly sneaking beneath her skirt and up her inner thighs. She moans loudly when his fingers find her and his eyes dart toward the door. He hitches her thigh up and and leans toward her, his breath misting over her ear.

“Think you can be quiet?”

She whimpers a little desperately when he nips at her throat, his fingers working deftly between her legs.

“I’ll take that as a no,” he whispers against her lips, kissing her again, swallowing her cries as she begins to shudder around his fingers.

At that moment, the door swings open.

“There you two are! What are you doing in here? We’ve been looking for you two for a pict– _OH MY GOD_.”

Martha stands framed in the doorway and Jack nearly collides into her. “Oh you’ve found them! Great!” He skids to a halt, and if the Doctor wasn’t so mortified he would have laughed at their twin expressions of shock. His brain slowly starts processing again and he drops Donna’s thigh, trying to surreptitiously wipe his fingers on his trousers.

“Were you two… were you two just...” Words desert Martha completely and she just stands there, her mouth opening and closing like a fish.

Donna looks like she may very well drop dead on the spot.

For a moment, speech evades all four of them as Donna turns progressively deeper scarlet next to him. There’s a funny rushing sound in his ears. Then Jack starts applauding.

"Well, well well," he laughs and Martha joins in, slightly hysterically. “I knew you were great at weddings."

“We’re… we’re not… we were just–” Planet-sized brain and he can’t form a single coherent sentence. Fat lot of use he is.

“It’s not what you think! We were just... having a chat!” Donna blurts out and Jack and Martha just laugh harder.

“I think we’ve broken your– er–  _our_ rule now,” the Doctor says quietly while Jack and Martha double over with laughter. He flinches at the dark look Donna shoots him and decides not to point out that this is completely her fault. Discretion is the better part of valour, he decides then and there. He’d read that somewhere. Never much abided by it, but it’s never too late for a change of heart.

“We’ll give you two a moment to get… er… collected–” Jack appraises Donna up and down, his thoughts completely transparent. The Doctor has to forcibly unclench his fists.  “Then come back and we’ll all get a nice pretty picture!”

He winks cheekily, his expression positively filthy, and tugs Martha out the door.

Donna collapses onto a chair.

“I think I’m sober now,” she says stonily. She looks a bit ill, actually. He opens his mouth to speak and she glares up at him.

“So help me Spaceman, if you say ‘I told you so’ or anything including the words ‘told you,’ ‘so,’ or ‘I’ I will slap you so hard you’ll still be feeling it in your 53rd regeneration.”

He shuts his mouth with a soft click.

“At least my mum still doesn’t know,” Donna says glumly after a while.

The Doctor rather thinks they shouldn’t tempt fate.

 

 


End file.
